the fan thing on my alternator is constantly coming lose and spinning independently of the pulley, making a massive racket. It is a toothed pulley which i have machined down to stop it fouling the arb bracket.
When the parts are assembled the fan is not "over" the woodruff key as it were so that cannot stop it spinning. I can't remember the standard assembly and wondered if there was a washer that spaced it out so it was "over" the woodruff key, or whether the friction from tightening on the pulley held it in place.
At the minute the latter is failing to do so.
Thanks for reading and merry christmas!
Danny
for future reference:
Got the alternator apart, because i had milled some of the pulley off it sat lower than the thread on the alternator, meaning the fan did not have adequate force applied to it to keep it in place
danny